Methods for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid and precursors thereof

ABSTRACT

The present invention is directed to processes associated with the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid (perzinfotel).

FIELD

The present invention relates to methods for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid and precursors thereto, which are useful in a variety of indications, compositions containing these compounds, and methods of their use.

BACKGROUND

U.S. Pat. No. 5,168,103 to Kinney et al. (“the '103 patent”) discloses certain [[2-(Amino-3,4-dioxo-1-cyclobuten-1-yl)amino]alkyl]acid derivatives. These derivatives are disclosed as competitive NMDA antagonists useful to treat certain central nervous system disorders such as convulsions, brain cell damage, and related neurodegenerative disorders. Side effects of one of the compounds disclosed in the '103 patent, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7-en-2-yl)ethyl]phosphonic acid (a/k/a perzinfotel or EAA-090) were evaluated in healthy human volunteers in a phase I clinical study in Europe, done in connection with developing the compound for treating stroke-related ischemia in patients (Bradford et al., Stroke and Cerebral Circulation, Abstract (1998)).

U.S. Pat. No. 7,098,200 to Brandt et al. (the '200 patent) discloses that perzinfotel is effective in producing antihyperalgesic effects in a variety of preclinical pain models. Perzinfotel has also been described as a potent, selective, competitive NMDA antagonist that exhibits a superior therapeutic index for efficacy versus psychotomimetic side effects (Childers et al., Drugs of the Future 27:633-638 (2002)). Perzinfotel possesses a bioisosteric squaric acid amide in place of the typical α-amino acid and is reported to be 10-fold selective for rodent NMDA receptors possessing the NR2A subunit (Sun et al., J. Pharm. Exp. Ther. 310:563-570 (2004)). Perzinfotel has demonstrated efficacy in animal models of inflammatory pain when administered both intraperitonealy and orally (Brandt et al., J. Pharm. Exp. Ther. 313:1379-1386 (2005)).

Perzinfotel has also been described as effective in mediating surprisingly robust anesthetic-sparing effects while also providing the surprising additional benefit of improved cardiopulmonary function relative to the anesthetic alone (U.S. Patent Publication No. 2009/0061024). That is, when used in conjunction with an anesthesia regimen, perzinfotel can be used for administering a reduced concentration of anesthetic than would otherwise be required in the absence of perzinfotel, to achieve an equivalent level of anesthesia.

Methods for the preparation of perzinfotel and related analogs have been described in Wilk et al. (U.S. Patent Publication No. 2005/0090470). Despite the exploration of a variety of chemistries to provide therapies based on perzinfotel, a continuing need exists for preparations which are efficient and amenable to large-scale syntheses. A need also exists for preparations which provide compounds free of impurities and any potentially harmful side-products.

SUMMARY

The present invention provides for an improved process for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid (perzinfotel), which has Formula I, and derivatives and precursors thereto.

One embodiment of the invention provides a process for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid comprising:

reacting 1,3-diaminopropane with dialkylvinylphosphonate to form N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester;

reacting the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-3-cyclobutene-1,2-dione to form [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester; and

hydrolyzing the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester to form the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid;

provided that (a) the reacting 1,3-diaminopropane with dialkylvinylphosphonate step is performed substantially in the absence of exogenous solvent; and/or (b) the reacting the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy (e.g. diethoxy)-3-cyclobutene-1,2-dione step is performed in an aprotic solvent.

Another embodiment of the invention provides a process for the preparation of N-(3-aminopropyl)aminoethanephosphonic acid dialkyl (e.g. diethyl) ester comprising:

reacting 1,3-diaminopropane with dialkylvinylphosphonate substantially in the absence of exogenous solvent to form N-(3-aminopropyl)aminoethane phosphonic acid dialkyl (e.g. diethyl) ester.

Another embodiment of the invention provides a process for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester comprising:

reacting N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-3-cyclobutene-1,2-dione in an aprotic solvent to form [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester.

Another embodiment of the invention provides a process for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid comprising:

hydrolyzing [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester in an aprotic solvent to form the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid.

Another aspect of the invention provides a composition comprising:

one or more of the compounds or intermediates described herein; and

one or more of: a base, an acid, a solvent, a hydrogenating agent, a reducing agent, an oxidizing agent, or a catalyst.

Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

DETAILED DESCRIPTION

The following definitions are provided for the full understanding of terms and abbreviations used in this specification.

As used herein and in the appended claims, the singular forms “a,” “an,” and “the” include the plural reference unless the context clearly indicates otherwise. Thus, for example, “a compound” is a reference to one or more compounds and equivalents thereof known to those skilled in the art, “a catalyst” refers to one or more catalysts and equivalents thereof known to those skilled in the art, and so forth.

The abbreviations in the specification correspond to units of measure, techniques, properties, or compounds as follows: “min” means minutes, “h” means hour(s), “μL” means microliter(s), “mL” means milliliter(s), “mM” means millimolar, “M” means molar, “N” means normal, “mmole” means millimole(s), “cm” means centimeters, “g” means grams, “NMR” means nuclear magnetic resonance, “GC” means gas chromatography, “MS” means mass spectrometry, “DEI” means desorption electron ionization and “FAB” means fast atom bombardment.

“Alkyl” refers to saturated aliphatic hydrocarbyl groups having from 1 to 6 carbon atoms (C₁-C₆ alkyl), and preferably 1 to 4 carbon atoms (C₁-C₄ alkyl). This term includes, by way of example, linear and branched hydrocarbyl groups such as methyl(CH₃—), ethyl(CH₃CH₂—), n-propyl (CH₃CH₂CH₂—), isopropyl((CH₃)₂CH—), n-butyl(CH₃CH₂CH₂CH₂—), isobutyl((CH₃)₂CHCH₂—), sec-butyl((CH₃)(CH₃CH₂)CH—), and t-butyl((CH₃)₃C—).

“Alkoxy” refers to —O-alkyl, where alkyl is defined above.

“Pharmaceutically acceptable salt” refers to pharmaceutically acceptable salts of a compound, which salts are derived from a variety of organic and inorganic counter ions well known in the art and include, by way of example only, sodium, aluminum, lithium, zinc, diethanolamine salts, potassium, calcium, magnesium, ammonium, and tetraalkylammonium; and when the molecule contains a basic functionality, salts of organic or inorganic acids, such as, hydrochloride, hydrobromide, hydroiodide, nitrate, sulfate, bisulfate, phosphate, acid phosphate, isonicotinate, acetate, lactate, salicylate, citrate, tartrate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisinate, fumarate, gluconate, glucaronate, saccharate, formate, benzoate, besylate, glutamate, methanesulfonate, ethanesulfonate, benzensulfonate, p-toluenesulfonate and pamoate (i.e., 1,1′-methylene-bis-(2-hydroxy-3-naphthoate)) salts. Certain compounds of the invention can form pharmaceutically acceptable salts with various amino acids as well. For a review on pharmaceutically acceptable salts see BERGE ET AL., 66 J. PHARM. SCI. 1-19 (1977), incorporated herein by reference.

“Perzinfotel” or “EAA-090” refers to the compound [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7-en-2-yl)ethyl]phosphonic acid, which has the following chemical structure (formula I):

The pharmaceutically acceptable salts are prepared by contacting a compound, such as the compound of formula (I) with an acid or salt such as, hydrochloric acid, hydrobromic acid, acetic acid, phosphoric acid, boric acid, perchloric acid, tartaric acid, maleic acid, citric acid, methanesulfonic acid, ascorbic acid, sodium iodide and the like. A solvent employed may be selected from ketones such as acetone, diethyl ketone, methyl ethyl ketone or their mixtures, methanol, ethanol, n-hexane, ethyl acetate, benzene, diethylamine, formaldehyde, chloroform, dichloromethane or mixture thereof.

At various places in the present specification, substituents of compounds are disclosed in groups or in ranges. It is specifically intended that the description include each and every individual subcombination of the members of such groups and ranges. For example, the term “C₁₋₆ alkyl” is specifically intended to individually disclose C₁, C₂, C₃, C₄, C₅, C₆, C₁-C₆, C₁-C₅, C₁-C₄, C₁-C₃, C₁-C₂, C₂-C₆, C₂-C₅, C₂-C₄, C₂-C₃, C₃-C₆, C₃-C₅, C₃-C₄, C₄-C₆, C₄-C₅, and C₅-C₆ alkyl.

The compounds described herein may be formulated for administration to humans and other animals orally, parenterally, sublingually, by aerosolization or inhalation spray, rectally, intracisternally, intravaginally, intraperitoneally, bucally, intrathecally or topically in dosage unit formulations containing conventional nontoxic pharmaceutically acceptable carriers, adjuvants, and vehicles as desired. Methods of formulation are well known in the art and are disclosed, for example, in Remington: The Science and Practice of Pharmacy, Mack Publishing Company, Easton, Pa., 21st Edition (2005), incorporated herein by reference.

Some of the compounds made in the process of the present invention may contain chiral centers and/or tautomers and such compounds may exist in the form of stereoisomers (i.e. enantiomers or diastereomers) or tautomers. The present invention includes all such stereoisomers, tautomers and any mixtures thereof including racemic mixtures. Further, the compounds of formula I may exist in unsolvated as well as in solvated forms with pharmaceutically acceptable solvents such as water, ethanol, and the like. In general, the solvated forms are considered equivalent to the unsolvated forms for the purpose of the present invention.

The compounds of formula I can be synthesized, for example, by the methods described below, or variations thereon as appreciated by the skilled artisan. All processes disclosed in association with the present invention are contemplated to be practiced on any scale, including milligram, gram, multigram, kilogram, multikilogram or commercial industrial scale.

The new process for the preparation of perzinfotel provided herein offers significant improvements over existing processes. Notably, in step 1 (see Scheme 1), no extensive purification of the product is required and the material can optionally be used “as is” in subsequent reactions. During reaction, the Step 2 product, precipitates from the reaction mixture as a solid with greater than about 95% purity and a yield in the range of 55-70%. Unreacted starting materials, dialkylated material (formed from the combination of Step 1 dialkylated product and diethyl squarate) and reaction by products remain in solution. In step 3, perzinfotel of high purity was obtained directly from the reaction mixture reducing the need for substantial additional work-up nor the treatment of strong acid/base.

One aspect of the present invention provides a process for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid comprising:

reacting 1,3-diaminopropane with dialkylvinylphosphonate to form N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester;

reacting the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-3-cyclobutene-1,2-dione to form [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester; and

hydrolyzing the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester to form the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid;

provided that (a) the reacting 1,3-diaminopropane with dialkylvinylphosphonate step is performed substantially in the absence of exogenous solvent; and/or (b) the reacting the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-3-cyclobutene-1,2-dione step is performed in an aprotic solvent.

In another embodiment, the reacting 1,3-diaminopropane with dialkylvinylphosphonate step is performed in a reaction mixture substantially in the absence of exogenous solvent.

In another embodiment, the reacting 1,3-diaminopropane with dialkylvinylphosphonate step comprises reacting in the presence of excess 1,3-diaminopropane.

In another embodiment, following formation of N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester, the process further comprises removing excess 1,3-diaminopropane by azeotropic distillation. Solvents suitably used in the azeotropic distillation include, among others, 1-butanol and xylenes (ortho, meta and para).

In another embodiment, the reacting N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-(e.g. diethoxy-)-3-cyclobutene-1,2-dione step is performed in an aprotic solvent. More particularly, the aprotic solvent is n-butyl acetate, iso-butyl acetate, methyl acetate, ethyl acetate, toluene, acetonitrile or a combination thereof, preferably ethyl acetate. More particularly, the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester precipitates out of a liquid phase. More particular still, the liquid phase is cooled to less than about 15° C. In another embodiment, the process further comprises filtering the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester from the liquid phase.

In another embodiment, the reacting 1,3-diaminopropane with dialkylvinylphosphonate step is performed in a reaction mixture substantially free of solvent; and

the reacting the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-3-cyclobutene-1,2-dione step is performed in an aprotic solvent.

In another embodiment, the hydrolyzing step is performed in an aprotic solvent, wherein the solvent is acetonitrile or dichloromethane.

In another embodiment, the hydrolyzing step comprises contacting the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester with trimethylsilyl bromide (TMS-Br) or trimethylsilyl iodide (TMS-I).

In another embodiment, the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid is formed in a reaction medium and the process further comprises contacting the reaction medium with water, wherein the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid precipitates out of the reaction medium. More particularly, the water in the reaction medium is first heated to above 50° C. and then cooled to below 15° C.

In another embodiment:

the dialkylvinylphosphonate is diethylvinylphosphonate;

the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester is N-(3-aminopropyl)aminoethanephosphonic acid diethyl ester; and

the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester is [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester.

In another embodiment:

the dialkylvinylphosphonate is dimethylvinylphosphonate;

the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester is N-(3-aminopropyl)aminoethanephosphonic acid dimethyl ester; and

the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester is [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dimethyl ester.

In another embodiment, the 3,4-dialkoxy-3-cyclobutene-1,2-dione is 3,4-diethoxy-3-cyclobutene-1,2-dione.

Another aspect of the invention provides a process for the preparation of N-(3-aminopropyl)aminoethanephosphonic acid dialkyl (e.g. diethyl) ester comprising:

reacting 1,3-diaminopropane with dialkylvinylphosphonate in a reaction mixture substantially in the absence of exogenous solvent to form N-(3-aminopropyl)aminoethane phosphonic acid dialkyl (e.g. diethyl) ester.

In another embodiment, the reacting 1,3-diaminopropane with dialkylvinylphosphonate step comprises reacting in the presence of excess 1,3-diaminopropane. In another embodiment, following formation of N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester, the process further comprises removing excess 1,3-diaminopropane by azeotropic distillation.

In another embodiment:

the dialkylvinylphosphonate is dimethylvinylphosphonate; and

the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester is N-(3-aminopropyl)aminoethanephosphonic acid dimethyl ester.

In another embodiment:

the dialkylvinylphosphonate is diethylvinylphosphonate; and

the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester is N-(3-aminopropyl)aminoethanephosphonic acid diethyl ester.

Another aspect of the invention provides a process for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester comprising:

reacting N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-3-cyclobutene-1,2-dione in an aprotic solvent to form [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester.

In another embodiment, the aprotic solvent is n-butyl acetate, iso-butyl acetate, ethyl acetate, methyl acetate, toluene, acetonitrile or a combination thereof.

In another embodiment, the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester precipitates out of a liquid phase.

In another embodiment, the liquid phase is cooled to less than about 15° C.

In another embodiment, the process further comprises filtering the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester from the liquid phase.

In another embodiment:

the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester is N-(3-aminopropyl)aminoethanephosphonic acid dimethyl ester; and

the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester is [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dimethyl ester.

In another embodiment:

the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester is N-(3-aminopropyl)aminoethanephosphonic acid diethyl ester; and

the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester is [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester.

In another embodiment, the 3,4-dialkoxy-3-cyclobutene-1,2-dione is 3,4-diethoxy-3-cyclobutene-1,2-dione.

Another aspect of the invention provides a process for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid comprising:

hydrolyzing [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester in an aprotic solvent (for example, acetonitrile or dichloromethane) to form the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid.

In another embodiment, the process further comprises preparing [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester by reacting the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-3-cyclobutene-1,2-dione, e.g. by processes described herein, to form [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester.

In another embodiment, the hydrolyzing step comprises contacting the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl (e.g. diethyl) ester with trimethylsilyl bromide (TMS-Br). In another embodiment, the aprotic solvent is acetonitrile. Alternatively, the aprotic solvent is dichloromethane. In another embodiment, the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid is formed in a reaction medium and the process further comprises contacting the reaction medium with water, wherein the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid precipitates out of the reaction medium. More particularly, the water in the reaction medium is first heated to above 50° C. and then cooled to below 15° C. In another embodiment, the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester is [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dimethyl ester. In another embodiment, the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester is [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester.

In another embodiment, any of the process steps are performed in a polar solvent or a nonpolar solvent. In another embodiment, any of the process steps are performed at or above 25° C.; or include the addition of one or more agents selected from the group consisting of a base, an acid, a solvent, a hydrogenating agent, a reducing agent, an oxidizing agent and a catalyst. In another embodiment, any of the process steps comprises a purification step comprising at least one of: filtration, extraction, chromatography, trituration, or recrystallization. In another embodiment, any of the process steps comprises an analytical step comprising liquid chromatography (LC), mass spectroscopy (MS), liquid chromatography/mass spectroscopy (LC/MS), gas chromatography (GC), gas chromatography/mass spectroscopy (GC/MS), nuclear magnetic resonance (NMR), thin layer chromatography (TLC), melting point (MP) analysis, optical rotation (OR) or elemental analysis.

Another aspect of the invention provides a composition or compound prepared by the processes described herein.

Compounds of the present invention are suitably prepared in accordance with the following general description and specific examples. Variables used are as defined for formula I, unless otherwise noted. Reagents used in the preparation of the compounds of this invention can be either commercially obtained or can be prepared by standard procedures described in the literature. As will be readily understood, functional groups present may contain protecting groups during the course of synthesis. In accordance with this invention, compounds of formula I may be produced by the following reaction schemes.

EXAMPLES Example 1 N-(3-aminopropyl)aminoethanephosphonic Acid Diethyl Ester

Version A:

To a 1 L, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet 1, 3-diaminopropane (285.5 g, 3.84 mole, 6.3 equiv) was added. Then diethyl vinylphosphonate 97% (100.5 g, 0.61 mole) was added drop-wise over one hour. The mixture was stirred overnight at room temperature and then toluene (300 mL) was introduced and the 1,3-diaminopropane and toluene were removed by azeotropic distillation under reduced pressure. The toluene (300 mL) and 1,3-diaminopropane azeotropic distillations were continued until 1,3-diaminopropane was not detected by GC analysis. The product was a colorless oil (142 g, 98% yield), purity 85.8% by GC analysis with 5.8% dialkylated product. NMR (CDCl₃, 400 Mhz): 1.18 (t, 6H), 1.47 (t, 2H), 1.80 (br, 3H), 1.83 (dt, 2H), 2.53 (t, 2H), 2.63 (dt, 2H), 2.76 (q, 2H), 3.95 (q, 4H).

Version B:

To a 1 L, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet 1, 3-diaminopropane (285.5 g, 3.84 mole, 6.3 equiv) was added. Then diethyl vinylphosphonate 97% (100.5 g, 0.61 mole) was added drop-wise over one hour. The mixture was stirred overnight at room temperature and then 1-butanol (300 mL) was introduced and the 1,3-diaminopropane and 1-butanol were removed by azeotropic distillation under reduced pressure. The 1-butanol (300 mL) and 1,3-diaminopropane azeotropic distillations were continued until 1,3-diaminopropane was not detected by GC analysis. The product was a colorless oil (140 g, 97.5% yield), purity 85.5% by GC analysis with 5.8% dialkylated product. NMR (CDCl₃, 400 Mhz): 1.18 (t, 6H), 1.47 (t, 2H), 1.80 (br, 3H), 1.83 (dt, 2H), 2.53 (t, 2H), 2.63 (dt, 2H), 2.76 (q, 2H), 3.95 (q, 4H).

Version C:

To a 1 L, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet 1, 3-diaminopropane (44.5 g, 0.605 mole, 10 equiv) was added. Then diethyl vinylphosphonate 97% (10 g, 0.0605 mole) was added drop wise over 1.5-2 hours. The mixture was stirred overnight at room temperature and then toluene (200 mL) was introduced and the 1,3-diaminopropane and toluene were removed by azeotropic distillation under reduced pressure. The toluene (200 mL) and 1,3-diaminopropane azeotropic distillations were continued until 1,3-diaminopropane was not detected by GC analysis. The product was a colorless oil (13.2 g, 92.7% yield), purity 89.5% by GC analysis with 3.0% dialkylated product. NMR (CDCl₃, 400 Mhz): 1.18 (t, 6H), 1.47 (t, 2H), 1.80 (br, 3H), 1.83 (dt, 2H), 2.53 (t, 2H), 2.63 (dt, 2H), 2.76 (q, 2H), 3.95 (q, 4H).

Example 2 [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic Acid Diethyl Ester

Version A:

To a 250 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, ethyl acetate (45 mL) was heated to 50-55° C. 3,4-diethoxy-3-cyclobutene-1,2-dione (20.5 g, 0.12 mole) was diluted with ethyl acetate to give a total volume of 30 mL and the solution transferred to an addition funnel. Similarly, N-(3-aminopropyl)aminoethanephosphonic acid diethyl ester (28.9 g, 0.105 mole) was mixed with ethyl acetate to give a total volume of 30 mL and transferred to an addition funnel. The two solutions were simultaneously added drop-wise into the preheated ethyl acetate over 2-3 hours. After the addition was complete, the mixture was cooled to 25° C. and then heated to 35° C. and held for one hour. The mixture was then cooled in an ice bath and held at 0-2° C. for one hour. The product was collected and washed with ethyl acetate (20 mL) and dried under vacuum to yield (23.3 g, 70%) and purity 96.6 w/w %. NMR (CDCl₃, 400 Mhz): 1.34 (t, 6H), 2.06 (m, 2H), 2.20 (dt, 2H), 3.50 (m, 4H), 4.05 (m, 2H), 4.15 (m, 4H), 7.87 (br 1H).). MS (DEI) M⁺ m/z 316. LC analysis (column: Microsorb-MV C-18, 150×4.6 mm: Eluent 30/70 MeOH/0.01 M NH₄H₂PO₄ pH 4.7; Flow rate: 1 mL/min; UV detector at 210 nm).

Version B:

To a 500 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, ethyl acetate (45 mL) was heated to 50-55° C. 3,4-diethoxy-3-cyclobutene-1,2-dione (34.6 g, 0.204 mole) was diluted with ethyl acetate to give a total volume of 60 mL and the solution transferred to an addition funnel. Similarly, N-(3-aminopropyl)aminoethanephosphonic acid diethyl ester (42.85 g, 0.192 mole) was mixed with ethyl acetate to give a total volume of 50 mL and transferred to an addition funnel. The two solutions were simultaneously added drop wise into the preheated ethyl acetate over 2-3 hours. After the addition was complete, the mixture was cooled to 25° C. and then heated to 35° C. and held for one hour. The mixture was then cooled in an ice bath and held at 0-2° C. for one hour. The product was collected and washed with ethyl acetate (20 mL) and dried under vacuum to yield (37.3 g, 65.6%) and purity 95.5 w/w %. NMR (CDCl₃, 400 Mhz): 1.34 (t, 6H), 2.06 (m, 2H), 2.20 (dt, 2H), 3.50 (m, 4H), 4.05 (m, 2H), 4.15 (m, 4H), 7.87 (br 1H).). MS (DEI) M⁺ m/z 316.

Version C:

To a 250 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, ethyl acetate (45 mL) was heated to 50-55° C. 3,4-diethoxy-3-cyclobutene-1,2-dione (15.5 g, 0.09 mole) was diluted with ethyl acetate to give a total volume of 30 mL and the solution transferred to an addition funnel. Similarly, N-(3-aminopropyl)aminoethanephosphonic acid diethyl ester (25.0 g, 0.105 mole) was mixed with ethyl acetate to give a total volume of 30 mL and transferred to an addition funnel. The two solutions were simultaneously added drop-wise into the preheated ethyl acetate over 2-3 hours. After the addition was complete, the mixture was cooled to 25° C. and then heated to 35° C. and held for one hour. The mixture was then cooled in an ice bath and held at 0-2° C. for one hour. The product was collected and washed with ethyl acetate (20 mL) and dried under vacuum to yield (15.8 g, 54.9%) and purity 97.5 w/w %. NMR (CDCl₃, 400 Mhz): 1.34 (t, 6H), 2.06 (m, 2H), 2.20 (dt, 2H), 3.50 (m, 4H), 4.05 (m, 2H), 4.15 (m, 4H), 7.87 (br 1H).). MS (DEI) M⁺ m/z 316.

Version D:

To a 250 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, ethyl acetate (45 mL) was heated to 50-55° C. 3,4-diethoxy-3-cyclobutene-1,2-dione (15.5 g, 0.09 mole) was diluted with ethyl acetate to give a total volume of 30 mL and the solution transferred to an addition funnel. Similarly, N-(3-aminopropyl)aminoethanephosphonic acid diethyl ester (22.5 g, 0.094 mole) was mixed with ethyl acetate to give a total volume of 30 mL and transferred to an addition funnel. The two solutions were simultaneously added drop-wise into the preheated ethyl acetate over 2-3 hours. After the addition was complete, the mixture is cooled to 25° C. and then heated to 35° C. and held for one hour. The mixture was then cooled in an ice bath and held at 0-2° C. for one hour. The product was collected and washed with ethyl acetate (20 mL) and dried under vacuum to yield (15.6 g, 54.2%) and purity 96.3 w/w %. NMR (CDCl₃, 400 Mhz): 1.34 (t, 6H), 2.06 (m, 2H), 2.20 (dt, 2H), 3.50 (m, 4H), 4.05 (m, 2H), 4.15 (m, 4H), 7.87 (br 1H). MS (DEI) M⁺ m/z 316.

Version E:

To a 250 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, toluene (50 mL) was heated to 50-55° C. 3,4-diethoxy-3-cyclobutene-1,2-dione (6.35 g, 0.037 mole) was diluted with toluene to give a total volume of 50 mL and the solution transferred to an addition funnel. Similarly, N-(3-aminopropyl)aminoethanephosphonic acid diethyl ester (8.58 g, 0.036 mole) was mixed with toluene to give a total volume of 50 mL and transferred to an addition funnel. The two solutions were concomitantly added drop-wise into the preheated toluene over 5-6 hours. After the addition was complete, the mixture was cooled to 25° C. The slurry was cooled in an ice bath and held at 0-2° C. for one hour. The product was collected and washed with toluene (20 mL) and dried under vacuum to yield (7.2 g, 63%) and purity 93.6 w/w %. NMR (CDCl₃, 400 Mhz): 1.34 (t, 6H), 2.06 (m, 2H), 2.20 (dt, 2H), 3.50 (m, 4H), 4.05 (m, 2H), 4.15 (m, 4H), 7.87 (br 1H). MS (DEI) M⁺ m/z 316.

Version F:

To a 250 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, acetonitrile (50 mL) was heated to 55-60° C. 3,4-diethoxy-3-cyclobutene-1,2-dione (6.35 g, 0.037 mole) was dissolved in acetonitrile (50 mL) and the solution transferred to an addition funnel. Similarly, N-(3-aminopropyl)aminoethanephosphonic acid diethyl ester (8.58 g, 0.036 mole) was dissolved in acetonitrile (50 mL) and transferred to an addition funnel. The two solutions were simultaneously added drop-wise into the preheated acetonitrile over 5-6 hours. The mixture was stirred overnight at room temperature. The acetonitrile was removed under reduced pressure and ethyl acetate (60 mL) was added to the residue and stirred for one hour. After cooling in an ice bath, the product was filtered and dried to yield (7.2 g, 63%) and purity 89.3 w/w %. NMR (CDCl₃, 400 Mhz): 1.34 (t, 6H), 2.06 (m, 2H), 2.20 (dt, 2H), 3.50 (m, 4H), 4.05 (m, 2H), 4.15 (m, 4H), 7.87 (br 1H). MS (DEI) M⁺ m/z 316. LC analysis (column: Microsorb-MV C-18, 150×4.6 mm: Eluent 30/70 MeOH/0.01 M NH₄H₂PO₄ pH 4.7; Flow rate: 1 mL/min; UV detector at 210 nm).

Version G:

To a 500 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, ethyl acetate (100 mL) was heated to 50-55° C. 3,4-diethoxy-3-cyclobutene-1,2-dione (34.63 g, 0.204 mole) was dissolved in ethyl acetate (30 mL) and the solution transferred to an addition funnel. Similarly, N-(3-aminopropyl)aminoethanephosphonic acid diethyl ester (50.02 g, 0.192 mole) was dissolved in ethyl acetate (15 mL) and 5% toluene (relative to the N-(3-aminopropyl)aminoethanephosphonic acid diethyl ester) added by weight. The solution was transferred to an addition funnel. The two solutions were simultaneously added drop-wise into the preheated ethyl acetate over 2-3 hours. After the addition was complete, the mixture was cooled to 25° C. and then heated to 35° C. and held for one hour. After cooling in an ice bath, the product was filtered and dried to yield (38.4 g, 66%) and purity 97.9 w/w %. NMR (CDCl₃, 400 Mhz): 1.34 (t, 6H), 2.06 (m, 2H), 2.20 (dt, 2H), 3.50 (m, 4H), 4.05 (m, 2H), 4.15 (m, 4H), 7.87 (br 1H). MS (DEI) M⁺ m/z 316.

Example 3 Perzinfotel [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic Acid

Version A:

To a 1000 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (49.3 g, 0.156 mole) dissolved in acetonitrile (400 mL) was added. Trimethylsilyl bromide (TMS-Br) (55.0 g, 0.36 mole) was added drop-wise over one hour with the temperature maintained below 30° C. The solution was stirred for one hour and then the temperature was increased to 45° C. for four hours. The solution was cooled to room temperature and poured into a vigorously stirred solution of water (81 mL) and acetonitrile (45 ml). During the addition a temperature of 20-25° C. was maintained and a slurry was produced. The slurry was stirred for 0.5 hours and room temperature and then held at 0-2° C. for one hour. The solid was collected and the wet cake was washed with acetonitrile pre-cooled to 0-5° C. (2×90 mL). In a 1000 mL, three-necked flask, equipped with a magnetic stirrer and a dropping funnel, the resulting wet cake (74 g) was suspended in water (270 mL). Then 30% sodium hydroxide (390 ml) was added until a pH of 12.5-13.5 was obtained and a solution results. The pH was adjusted to pH 0.5-1.5 by the slow addition of 6N hydrochloric acid (57 mL) while maintaining the pot temperature at 20-25° C. The slurry was cooled to 0-5° C. and held for thirty minutes. The product was collected by filtration and washed with water pre-cooled to 0-5° C. (2×20 mL). The wet cake weighed 65.5 grams and was in a vacuum oven at 63-65° C. for twelve hours. The crude perzinfotel weighs 38.4 grams after drying.

To a 1000 mL, three-necked flask, equipped with a magnetic stirrer and a reflux condenser was added the crude perzinfotel followed by water (435 mL). The mixture was heated to 90-95° C. until a clear yellow solution was obtained. The solution was held at 90-95° C. for thirty minutes. The solution was allowed to cool slowly to room temperature (˜1° C./minute). Crystallization began at about 50-55° C. After one hour at room temperature, the slurry was then cooled and held at 0-2° C. for one hour. The solid was collected and washed with cold water (5 mL) and dried in a vacuum oven at 63-65° C. for twenty-four hours. Perzinfotel (34.9 g) was obtained with a total yield of 86% and w/w % purity of 98.9. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). -FAB [M-H]⁺ m/z 259.

Version B:

To a 500 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (15 g, 0.048 mole) dissolved in acetonitrile (120 mL) was added. Trimethylsilyl bromide (TMS-Br) (16.9 g, 0.11 mole) was added drop-wise over one hour with the temperature maintained below 30° C. The solution was stirred for one hour and then the temperature was increased to 45° C. for four hours. The solution was cooled to room temperature and poured into water (30 mL) and a slurry was produced. The slurry was stirred for 0.5 hours and room temperature and then held at 0-2° C. for one hour. The solid was collected and the wet cake was suspended in water (total volume 140 mL) and heated to 95-100° C. until a clear yellow solution was obtained. The solution was allowed to cool slowly to room temperature and after one hour at room temperature the slurry was cooled and held at 0-2° C. for one hour. The solid was collected and washed with cold water (5 mL) and dried in a vacuum oven at 63-65° C. for twenty-four hours. Perzinfotel was obtained with a total yield of 76% and w/w % purity 97.8 NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). -FAB [M-H]⁻ m/z 259.

Version C:

To a 500 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (15 g, 0.048 mole) dissolved in acetonitrile (120 mL) was added. Trimethylsilyl bromide (TMS-Br) (16.9 g, 0.11 mole) was added drop-wise over one hour with the temperature maintained below 30° C. The solution was stirred for one hour and then the temperature was increased to 45° C. for four hours. The solution was cooled to room temperature and poured into water (30 mL) and a slurry is produced. The slurry was stirred for 0.5 hours at room temperature and then held at 0-2° C. for one hour. The solid was collected and the wet cake was suspended in water (total volume 60 mL) and the resulting slurry was heated at 50° C. for one hour. The slurry was allowed to cool slowly to room temperature and after one hour at room temperature the slurry was cooled and held at 0-2° C. for one hour. The solid was collected and washed with cold water (5 mL) and dried in a vacuum oven at 63-65° C. for twenty-four hours. Perzinfotel was obtained with a total yield of 60% and w/w % purity 98.5. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1 Ht 2). Analysis -FAB [M-H]⁻ m/z 259.

Version D:

To a 1 L, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (30 g, 0,095 mole) dissolved in acetonitrile (180 mL) was added. Trimethylsilyl bromide (TMS-Br) (33.39 g, 0.218 mole) was added drop-wise over ten minutes with the temperature maintained below 30° C. At the end of addition the temperature was increased to 50° C. for four hours. The solution was cooled to room temperature and poured into water (50 mL) heated to 50° C. and a slurry is produced. The slurry was heated at 78° C. for two hours, cooled to room temperature and then and held at 0-2° C. for one hour. The solid was collected washed with cold water (5 mL) and dried in a vacuum oven at 63-65° C. for twenty-four hours. Perzinfotel was obtained with a total yield of 91% and w/w % purity 98.1. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H); FAB [M-H]⁻ m/z 259.

Version E:

To a 1 L, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (30 g, 0.095 mole) dissolved in acetonitrile (180 mL) is added. Trimethylsilyl bromide (TMS-Br) (34.8 g, 0.229 mole) is added drop wise over ten minutes. At the end of addition the temperature was increased to 50° C. for seven hours. Water (50 mL) is added to the hot solution and a slurry is produced. The temperature is increased to 78° C. and held for one hour, cooled to room temperature and then and held at 0-2° C. for one hour. The solid was collected washed with acetonitrile (40 mL), followed by water (40 mL), and dried in a vacuum oven at 63-65° C. for eighteen hours. Perzinfotel was obtained with a total yield of 89% and w/w % purity 95.4. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). -FAB [M-H]⁻ m/z 259.

Version F:

To a 125 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (5 g, 0.016 mole) and sodium iodide (5.52 g, 0.0368 mole) are dissolved in acetonitrile (40 mL) is added. Trimethylsilyl chloride (TMS-Cl) (4.0 g, 0.0368 mole) is added drop wise over ten minutes with the temperature maintained below 30° C. The solution is stirred for one hour and then allowed to stir overnight at room temperature. Water (8.5 mL) was added to the thick slurry and stirring continued 0.5 hours and then held at 0-2° C. for one hour. The solid was collected and washed with cold water (2 mL) and dried in a vacuum oven at 63-65° C. for twenty four hours. Perzinfotel was obtained with a total yield of 89% and purity 94.7%. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). -FAB [M-H]⁻ m/z 259.

Version G:

To a 125 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (2.5 g, 0.008 mole) and sodium iodide (2.79 g, 0.0184 mole) are dissolved in toluene (1.5 mL) and acetonitrile (20 mL). Trimethylsilyl chloride (TMS-Cl) (4.0 g, 0.0368 mole) is added drop wise over ten minutes with the temperature maintained below 30° C. The solution is stirred for one hour and then allowed to stir overnight at room temperature. Water (4.0 mL) was added to the thick slurry and stirring continued 0.5 hours and then held at 0-2° C. for one hour. The solid was collected and washed with cold water (2 mL) and dried in a vacuum oven at 63-65° C. for twenty four hours. Perzinfotel was obtained with a total yield of 89% and purity 97.7% w/w %. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). -FAB [M-H]⁻ m/z 259.

Version H:

To a 250 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (0.3 g, 0.001 mole) dissolved in toluene (3 mL) is added. Trimethylsilyl bromide (TMS-Br) (0.35 g, 0.0023 mole) is added drop wise over ten minutes with the temperature maintained below 30° C. The solution is stirred for one hour and then the temperature was increased to 50° C. for sixteen hours. The solution was cooled to room temperature and poured onto water (1 mL) and a slurry is produced. The slurry is stirred for 0.5 hour and room temperature and then and held at 0-2° C. for one hour. The solid was collected and washed with cold water (1 mL) and dried in a vacuum oven at 63-65° C. for twenty four hours. Perzinfotel was obtained with a total yield of 65% and purity 97.4 w/w %. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). -FAB [M-H]⁻ m/z 259.

Version I:

To a 125 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (2.5 g, 0.008 mole) and potassium iodide (3.05 g, 0.0184 mole) are dissolved in acetonitrile (40 mL) is added. Trimethylsilyl chloride (TMS-Cl) (4.0 g, 0.0368 mole) is added drop wise over ten minutes with the temperature maintained below 30° C. The solution is stirred for one hour and then allowed to stir overnight at room temperature. Water (4.0 mL) was added to the thick slurry and stirring continued 0.5 hours and then held at 0-2° C. for one hour. The solid was collected and washed with cold water (2 mL) and dried in a vacuum oven at 63-65° C. for twenty four hours. Perzinfotel was obtained (1.5 g) with a total yield of 70% and purity 95.8% w/w %. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). -FAB [M-H]⁻ m/z 259.

Version J:

[2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (0.6 g, 0.0019 mole) is dissolved in concentrated hydrochloric acid (0.8 mL) and heated to 90° C. for twenty-four hours. After cooling to room temperature, water (1 mL) and acetonitrile (10 mL) are added to the yellow solution. The yellow solid was collected and dried in a vacuum oven at 63-65° C. for twenty four hours. Perzinfotel was obtained (0.1 g) with a total yield of 19% and purity 86.7% w/w %. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). ⁻ m/z 259.

Version K:

[2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (0.6 g, 0.0019 mole) and is dissolved in concentrated sulfuric acid (0.8 mL) and heated at 90° C. for twenty-four hours. After cooling to room temperature, water (3 mL) was added followed by 50% sodium hydroxide until a pH 13. To the yellow, basic solution, 6N hydrochloric acid was added to achieve pH 1. To the gel obtained was added acetonitrile (15 mL) to give a white solid. The white solid was collected and dried in a vacuum oven at 63-65° C. for twenty four hours. Perzinfotel was obtained (0.1 g) with a total yield of 19% and purity 84.8% w/w %. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). FAB [M-H]⁻ m/z 259.

Version L:

To a 1 L, three-necked flask, equipped with a magnetic stirrer and nitrogen, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (30 g, 0.095 mole) dissolved in acetonitrile (180 mL) is added. Trimethylsilyl bromide (TMS-Br) (33.39 g, 0.218 mole) was added drop-wise over ten minutes with the temperature maintained below 30° C. At the end of addition the temperature was increased to 50° C. for four hours. The solution was cooled to room temperature and poured onto water (50 mL). The slurry was then and held at 0-2° C. for one hour. The crude solid was collected. The wet crude solid was reslurried in methanol (10 mL solvent per g of wet solid) and heated to 60° C. for 3 hours. The slurry was allowed to slowly cool to room temperature. The yellow solid was collected and dried in a vacuum oven at 63-65° C. for twenty four hours. Perzinfotel was obtained with a w/w % purity 96.3. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). FAB [M-H]⁻ m/z 259.

Version M:

To a 250 mL, three-necked flask, equipped with a magnetic stirrer and a nitrogen inlet, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (15.2 g, 0.048 mole) is suspended in acetonitrile (60 mL). Trimethylsilyl bromide (TMS-Br) (16.8 g, 0.115 mole) is added drop wise over ten minutes to the thin slurry. At the end of addition the temperature was increased to 50° C. for two hours. Water (15 mL) is added to the hot solution and a slurry is produced. The temperature is increased to 78° C. and held for one hour, cooled to room temperature and then and held at 0-2° C. for one hour. The solid was collected washed with acetonitrile (20 mL) and dried in a vacuum oven at 63-65° C. for eighteen hours. Perzinfotel was obtained as a dry solid (11.8 grams) with a total yield of 97% and w/w % purity 88.5. NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). -FAB [M-H]⁻ m/z 259.

From the above procedure, Perzinfotel (11.1 grams) was suspended in water (total volume 55 mL) and heated to 95-100° C. until a thin slurry was obtained. The slurry was allowed to cool slowly to room temperature and after one hour at room temperature the slurry was cooled and held at 0-2° C. for one hour. The solid was collected and washed with cold water (3 mL) and dried in a vacuum oven at 63-65° C. for twenty-four hours. Perzinfotel (9.2 grams) was obtained as a yellow solid with an overall yield of 76% and w/w % purity 97.1 NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). -FAB [M-H]⁻ m/z 259.

Version N:

To a 250 mL, three-necked flask, equipped with a magnetic stirrer, reflux condenser and a nitrogen inlet, [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester (15.2 g, 0.048 mole) is dissolved in dichloromethane (60 mL). Trimethylsilyl bromide (TMS-Br) (16.9 g, 0.1159 mole) is added drop wise over ten minutes. At the end of addition, the temperature was increased to 35° C. for nine hours. Water (15 mL) is added to the solution and a slurry is produced. The condenser is set for downward distillation and the methylene chloride collected, As the distillation proceeded, water (45 mL) is added. The crude Perzinfotel was now suspended in water (total volume 60 mL) and heated to 80°-85° C. until a thin slurry was obtained. The slurry was allowed to cool slowly to room temperature and after one hour at room temperature the slurry was cooled and held at 0-2° C. for one hour. The solid was collected and dried in a vacuum oven at 63-65° C. for twenty-four hours. Perzinfotel (10.8 grams) was obtained as a pale yellow solid with an overall yield of 86.4% and w/w % purity 98.7 NMR (DMSO-d₆, 400 Mhz): 1.90 (m, 4H)), 3.25 (m, 2H), 3.36 (m, 2H), 3.84 (q, 4H), 8.45 (s, 1H). -FAB [M-H]⁻ m/z 259. 

1. A process for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid comprising: reacting 1,3-diaminopropane with dialkylvinylphosphonate to form N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester; reacting the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-3-cyclobutene-1,2-dione to form [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester; and hydrolyzing the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester to form the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid; provided that (a) the reacting 1,3-diaminopropane with dialkylvinylphosphonate step is performed substantially in the absence of exogenous solvent; and/or (b) the reacting the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-3-cyclobutene-1,2-dione step is performed in an aprotic solvent. 2.-4. (canceled)
 5. The process of claim 1, wherein the reacting 1,3-diaminopropane with dialkylvinylphosphonate step comprises reacting in the presence of excess 1,3-diaminopropane.
 6. (canceled)
 7. The process of claim 1, wherein the aprotic solvent is n-butyl acetate, iso-butyl acetate, methyl acetate, ethyl acetate, toluene, acetonitrile or a combination thereof.
 8. (canceled)
 9. The process of claim 1, wherein the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester precipitates out of a liquid phase.
 10. The process of claim 9, wherein the liquid phase is cooled to less than about 15° C.
 11. (canceled)
 12. The process of claim 1, wherein the hydrolyzing step comprises contacting the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester with trimethylsilyl chloride (TMS-Cl), trimethylsilyl bromide (TMS-Br) or trimethylsilyl iodide (TMS-I).
 13. The process of claim 1, wherein the hydrolyzing step is performed in acetonitrile or dichloromethane.
 14. The process of claim 1, wherein the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid is formed in a reaction medium upon contacting the reaction medium with water, wherein the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid precipitates out of the reaction medium.
 15. The process of claim 14, wherein the water in the reaction medium is first heated to above 50° C. and the quenched reaction medium is then cooled to below 15° C. 16.-18. (canceled)
 19. A process for the preparation of N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester comprising: reacting 1,3-diaminopropane with dialkylvinylphosphonate in a reaction mixture substantially in the absence of exogenous solvent to form N-(3-aminopropyl)aminoethane phosphonic acid dialkyl ester.
 20. The process of claim 19, wherein the reacting 1,3-diaminopropane with dialkylvinylphosphonate step comprises reacting in the presence of excess 1,3-diaminopropane.
 21. The process of claim 20, wherein following formation of N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester, the process further comprises removing excess 1,3-diaminopropane by azeotropic distillation. 22.-23. (canceled)
 24. A process for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-ypethyl]phosphonic acid dialkyl ester comprising: reacting N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-3-cyclobutene-1,2-dione in an aprotic solvent to form [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester.
 25. (canceled)
 26. The process of claim 24, wherein the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester precipitates out of a liquid phase.
 27. The process of claim 26, wherein the liquid phase is cooled to less than about 15° C.
 28. The process of claim 26, wherein the process further comprises filtering the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester from the liquid phase. 29.-31. (canceled)
 32. A process for the preparation of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid comprising: hydrolyzing [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester in an aprotic solvent to form the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid.
 33. The process of claim 32, in which the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester is prepared by a process comprising reacting the N-(3-aminopropyl)aminoethanephosphonic acid dialkyl ester with 3,4-dialkoxy-3-cyclobutene-1,2-dione to form [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester.
 34. (canceled)
 35. The process of claim 32, wherein the hydrolyzing step comprises contacting the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid dialkyl ester with trimethylsilyl bromide (TMS-Br).
 36. (canceled)
 37. The process of claim 32, wherein the [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid is formed in a reaction medium and the process further comprises contacting the reaction medium with water, wherein the [2-(8,9-dioxo-2,6-diazabicyclo [5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid precipitates out of the reaction medium.
 38. The process of claim 37, wherein the water in the reaction medium is first heated to above 50° C. and the quenched reaction medium is then cooled to below 15° C. 39.-45. (canceled) 